This invention relates to an apparatus for equalizing the tension of a ribbon in a cassette.
In recent years there has been a trend to employ inked-ribbon cassettes for use with business machines like, for example, accounting machines, printers, and typewriters. These cassettes are usually low cost items which facilitate the loading of an inked ribbon into a business machine and eliminate the messy operation usually associated with loading reels of inked ribbons into the machine.
One type of ribbon cassette currently employed on business machines is the stuffed ribbon variety. This type of cassette has a storage chamber wherein convolutions or folds of the ribbon are stored. The cassette has an internal feed or drive mechanism which pulls the ribbon from an exit area of the cassette past a printing station and pulls it back to an entrance area of the cassette where the ribbon is pushed back into the chamber of the cassette by the internal feed mechanism which is usually externally powered. The convolution or folds of the ribbon are formed in the chamber near the entrance area, and the chamber is usually designed to facilitate the flow of the convolutions of ribbon in the chamber from the entrance area to the exit area of the cassette.
One of the problems associated with ribbon cassettes of the type described in the previous paragraph is that during the initial loading of ribbon into the cassette, the initial convolutions or folds of ribbon which are formed in the now empty cassette are quite large compared to those which are later formed when the cassette approaches the fully loaded condition. These large convolutions of ribbon present a problem when the cassette is initially used on a business machine because they are more difficult to pull out of the exit area of the cassette than are the small ones. The large convolutions present an increased drag or tension on the ribbon causing the ribbon to be frayed when the ribbon is driven by its own internal feed or drive mechanism. Also, if the ribbon does not advance during a printing operation, repeated use of one area of the ribbon may cause the ribbon to wear through at that area, thereby shortening the life of the ribbon and cassette.
The present invention obviates the problems mentioned in the previous paragraph in that it reduces or eliminates the premature failure of a ribbon cassette due to the excessive drag or tension created by the large convolutions of ribbon formed in a cassette during the initial loading thereof.